Enhancement of {110}<001> Texture by Controlling α-phase and Achievement of Low Young's Modulus and High Strength in Metastable β-type Ti–Zr-Based Alloys

Achieving both low Young's modulus and high strength, which are essentially in a trade-off relationship, is an important challenge in the field of biomaterials. Herein, the effects of oxygen and nitrogen addition on mechanical properties and recrystallization texture of a metastable Ti–18Zr–3Nb–3Sn–2Mo alloy are investigated. Both oxygen and nitrogen additions increase the apparent yield stress and tensile strength. The N-added alloy exhibits an exceptionally strong {110}<001> texture, commonly referred to as Goss texture, leading to a lower Young's modulus when compared with the O-added alloy. It is found that the formation and subsequent dissolution of the α-phase plays an important role in the development of recrystallization texture. The {110}<001> texture can be enhanced in the O-added alloy by a two-step heat treatment, the first step to form the α-phase and the second step to dissolve the α-phase during recrystallization. An excellent combination of a low Young's modulus and a high yield stress is achieved in the O-added alloy subjected to the two-step heat treatment.